It was proposed at the 34th Conference of the Long Term Evolution (LTE) Advanced Standardization Subgroup that, to further improve a total throughput rate and an average throughput rate that are of cell users, there is a need to specially conduct research on advanced radio interface technologies for 4th Generation (4G) systems (Advanced Radio Interface TechnologIes for 4G SysTems, (ARTIST4G)). A dynamic three-dimensional (3D) beamforming technology and a 3D multi-antenna technology are key technologies for improving a throughput rate of cell-edge users and a total throughput rate and an average throughput rate that are of cell users, and attract great attention from the industry.
In an existing active antenna system, 3D beamforming may be performed. Refer to FIG. 1 (crosswise arranged antennas are dual-polarized antennas (there are two polarization directions at positive 45 degrees and at negative 45 degrees), and antennas arranged in parallel are co-polarized antennas (there is only one polarization direction)). One form in the active antenna system is a two-dimensional (2D) planar antenna array, and the antenna array have both a horizontal dimension and a vertical dimension. By sending pilot signals, a base station obtains channel state information of the 2D antenna array that is fed back by a terminal, so that a beam aims at a target user in 3D space, signal receive power is further increased, a signal to interference plus noise ratio is increased, and a throughput of the entire system is further improved.
In a process of implementing the foregoing 3D beamforming technology, the inventor finds that in the prior art, a relatively large quantity of antennas provided in an antenna array causes an increase in pilot signal overheads.